CLASS - 11TH BIOLOGY
CHAPTER - 1 THE LIVNG WORLD
CHAPTER - 1 THE LIVNG WORLD
What is life →
It is unique, complex organisations of molecules that express itself through chemical reaction which leads to - Growth, Development, Adaptation, Responsiveness, Reproduction.
Characteristics of living beings
1) Definet shape and size
2) Organisation
3) Growth and development
4) Metabolism
5) Reproduction
6) Homeostasis
7) Consciousness
8) Adaptation
9) Evolution
10) Repair and Regeneration
11) Ageing
12) Death
1) Definit Shape and Size
a) Living organism have defined shape and size which may change within a narrow range.
b) Due to this property, living organism are called morphous.
c) Non living matter is termed amorphous.
2) Organisations
a) It is differentiation of a body into smaller unit and sub - unit which are arranged in an orderly manner.
b) Due to presence of organisations, a living being is called organism.
Like = Cell → Tissue → Organ → Organ system → Organism
3) Growth and development
b) Growth is permanent and irreversible change in the size of cell an organ or whole organism usually accompanied by increase in - a) Dry weight, b) mass and c) Number of cell.
B) DEVELOPMENT is the sum total of change that occur in an organ or organism its lifetime.
Increase in mass and increase in number of individuals are twin characters of growth.
In plants, growth continues throughout life as they have meristematic areas where cell division occurs regularly.
IN ANIMAL - Growth upto a certain age after which cell divided only to replace worn out and lost cell.
Three process are involved in growth
Increase in mass and increase in number of individuals are twin characters of growth.
In plants, growth continues throughout life as they have meristematic areas where cell division occurs regularly.
IN ANIMAL - Growth upto a certain age after which cell divided only to replace worn out and lost cell.
Three process are involved in growth
1) cell division
2) Cell enlargement
3) Secretion of Apoplasmic substances
2) Cell enlargement
3) Secretion of Apoplasmic substances
Growth and development
↓ ↓
Intussusception Accretion
1) Intussusception - Living organism show internal growth due to additional of materials and formation of cell inside their body.
2) Accretion - Non living articles increase in size due to addition of similar materials on their surface.
NOTE - 1 Growth cannot be taken as defining properties of living organism.
Examples - Stone, Crystals, Mountain.
Growth producingsubstances
1) Protoplasmic ( There are components matter like
cytoplasmic and nucleus)
2) Apoplasmic ( There are non living materials formed by cells
Eg - Cell wall, bone matrix, fibres. )
4) METABOLISM
It is sum total of various biochemical reaction occuring in a cell.
NOTE 2 - It is defining properties of all livingorganisms.
1) Metabolism - Non living object exhibits Metabolism
Metabolic reactions can be demonstrated outside the body in cell free systems.
An isolated metabolic reaction in a test tube is neither living nor non living.
NOTE - METABOLISM IS A DDDEDEFINING FEATURES OF ALL LIVNG ORGANISMS WITHOUT EXCEPTION.
Isolated metabolic reaction in vitro are non living things but surely living reactions.
Note - cellular organisation of the body is the defining features of life form.
Metabolism
↓ ↓
Anabolism Catabolism
1) Anabolism
It is also called constructive Metabolism.
It includes all the building up reactions.
It involves synthesis of complex substances.
Eg - Photosynthesis.
2) Catabolism
It is also called destructive Metabolism.
It includes all the breakdown reactions
It involves breakdown of complex substances.
Eg - Respiration, Digestion.
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